1. Field of the Invention
The present invention relates generally to a boostbuck circuit and more particularly, to a self-coupled transformer boostbuck circuit that provides multiple voltage outputs.
2. Description of the Related Art
In a regular LLC resonant converter, the secondary wide has +12V, +5V and +3.3V voltage outputs drawn from the middle part. However, when the load at one voltage output of the LLC resonant converter is changed, the other voltage output will be affected to cause cross regulation. For example, when the load at the +12V output is changed, the voltage outputs +5V and +3.3V will be relatively changed; when the load at the +5V is changed, the voltage outputs +12V and +3.3V will be relatively changed. Thus, these three voltage outputs affect one another, causing a cross regulation error.
Therefore, it is desirable to provide a boostbuck circuit that eliminates the aforesaid problem.